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IV Workshop Atlas-CMS

IV Workshop Atlas-CMS. Aspettative di ATLAS e CMS per il pilot run 2007 e inizio 2008. “triggers, rates, calibrazioni, validazione detector, possibili misure…”. U.Gasparini, Univ.di Padova & INFN Padova A.Nisati, INFN Roma1. Sommario. scenario di startup per LHC: “pilot run”del

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IV Workshop Atlas-CMS

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  1. IV Workshop Atlas-CMS Aspettative di ATLAS e CMS per il pilot run 2007 e inizio 2008 “triggers, rates, calibrazioni, validazione detector, possibili misure…” U.Gasparini, Univ.di Padova & INFN Padova A.Nisati, INFN Roma1 Atlas-CMS workshop, Bologna 24/11/06

  2. Sommario • scenario di startup per LHC: “pilot run”del 2007, run di fisica del 2008 (brevi richiami) • Rivelatori: cosa ci aspettiamo di avere (in termini di calibrazioni, allineamenti, conoscenza campo magnetico, prestazioni…) • Primo “commissioning su fascio” • Triggers • Prima fisica Atlas-CMS workshop, Bologna 24/11/06

  3. 2007 LHC pilot run Assunzioni “ragionevoli”…: (~3 “settimane”, ad una efficienza “globale” del DAQ di ~ 50% ) “Pilot run” (450 + 450 GeV ): luminosita’: L= 1029 – 1030 cm-2s-1 Dt~106s  Ldt  1029106= 1035 =100 nb-1 M.Lamont Sept.’06 Atlas-CMS workshop, Bologna 24/11/06

  4. 2008 :Physics pilot run Stage I II III LHC :2008 physics run No beam Beam Hardware commissioning to 7 TeV Should look something like… Machine Checkout 1 month Commissioning with beam 2 months Provisional Pilot Physics 1 month [vedi backup slide] Nessuno puo’ dire **oggi** cosa ci sara’ in aggiunta nel 2008 ( 10/100 pb-1? 1 fb-1 sembra **molto** ottimistico…) Atlas-CMS workshop, Bologna 24/11/06

  5. Rivelatori @ startup: tracciatori L’ Inner Detector di ATLAS • Pixels: 1700 moduli, 80 milioni di celle - misura 3 punti/traccia con accuratezza 10 mm • (115mm nella coordinata z) • SCT: 4000 moduli, 6 milioni di canali - 4 punti/traccia con accuratezza 20 mm • (400mm in the z-coordinate) • TRT: 370k straws – 36 punti con accuratezza 200 mm accuracy - C wheels initialmente • non installate • SIstemi estremamente complessi – mesi di commissioning anche prima dei dati di fisica… Atlas-CMS workshop, Bologna 24/11/06

  6. Accuratezza in posizione, ricostruzione di traccia con allineamento “as installed” • Individual modules located on supports to 2-100m in r- • Support structures (layers/disks/modules) positioned to 20-200m • Interferometry can monitor SCT deformation induced by environmental condition at 1 m level • Whole ID positioned to within 500(200) m in X(Y) wrt the solenoid axis • Possible rotation up to 0.1 mrad wrt beamline, about 0.1 mrad to solenoid axis • Start system debug and alignment with cosmics and beam-gas interactions • How well will tracks be found initially ? • Use standardtrackfinding • Misalign all modules (SCT/pixel) by ‘local’ installation precision • Misalign all barrels/disks by RMS 100 m • Reasonable estimate of installed precision • Four examples – different misalignments • Study track finding efficiency wrt perfect align. • 94% efficiency for ‘local’ misalignments • 40-60% efficiency for installed precision • Tracks can still be found (with std cuts) • Should really run with relaxed tolerances • With 500 m RMS, serious degradation • Sometimes very few tracks found • Important to build as precisely as possible Atlas-CMS workshop, Bologna 24/11/06

  7. Analisi di muoni cosmici:posizionamento dei moduli SCT Gli spostamenti relativi TRT ↔SCT ottenuti dai dati dei cosmici sono ben compatibili con le misure del survey fatte in fase di installazione: 290 m vs 300 m Similmente per le rotazioni: 0.28 mrad vs 0.22 mrad mm Individual module position to less than 50 m mm Atlas-CMS workshop, Bologna 24/11/06

  8. Allineamento con i dati dalle collisioni pp : stima delle precisioni ottenibili • Calculate r- alignment precision from one day of low luminosity running (here L=1033 cm-2s-1 was assumed): • Use all tracks in modules, or only overlaps (few 1%) • Results given for middle pixel barrel, and 2nd SCT barrel • The same is for L=1031 cm-2s-1 in the case of hadrons; scale by 10 for muons • Statistics to align pixels to 1-2 m and SCT to 2-3 m using 1 day of data taking • Limited by data recording rate rather than luminosity • But systematics will also be important – can make a start with little data La statistica non e’ un problema: sara’ piu’ importante la comprensione degli effetti sistematici Atlas-CMS workshop, Bologna 24/11/06

  9. Rivelatori @ startup: tracciatori in CMS Il sistema di allineamento delle camere a mu : Pixel: 720 moduli (barile) Si-Tracker: ~15,000 moduli 250 camere DT L’ obiettivo finale dell’ allineamento (ovvero: essere confrontabile con la risoluzione intrinseca) 468 Camere CSC [ LA sfida per l’allineamento con le tracce…] Strategia a due stadi… [vedi backup slide per maggiori dettagli] Nota: il Pixel det. NON sara’ installato nel pilot run 2007 Atlas-CMS workshop, Bologna 24/11/06

  10. Rivelatori @ startup: Tracciatore CMS Tracker: “TIB” layer4 (I) si punta a ~ 30 mm nel 2008; raggiungibile… (II) Atlas-CMS workshop, Bologna 24/11/06

  11. Rivelatori@startup: tracciamento • ~ 15 tracce/evento nell’ accettanza del Tracciatore, con momento medio di ~ 0.5 GeV. • L’ effetto dello scattering multiplo e’ importante • ~10% delle tracce ha pT>2 GeV @ ECM=14 TeV • Ipotizzando di avere un trigger MB ~ 10 Hz (~10% della bandwidth totale; potrebbe essere maggiore, data la piccola dimensione degli eventi): • 2 tracks/ sec ~105 tracce/giorno CMS Pixel, 720 modules “iterative Hits & Impact parameters method”: Convergenza a sx=sy~10mm OK Atlas-CMS workshop, Bologna 24/11/06

  12. Rivelatori @ medio/lungo termine Recente risultato (CMS Computing&Sw Challenge ’06): CMS Si Tracker, ~15,000 moduli 106 Z mm (iterative Hits & Impact Parameters method) Allineamento con le tracce dei TOB rods: Misalign.~100 mm risultato sometime in 2008? Atlas-CMS workshop, Bologna 24/11/06

  13. dn/ dt MDT calibration : to + r-t relation • ultimate accuracy in to : 0.4 ns • needs ~ 104 hits/tube • O (109) -triggers (geometry +  included) to (to) (ns) t(ns) 0.4 ns 104 n Calibrazione del rivelatore di Muoni: ATLAS • before pp data : • cosmics during commissioning (sys shift) • cosmics in ATLAS • Use RPC: few ns accuracy • Use track fit Atlas-CMS workshop, Bologna 24/11/06

  14. MDT calibration : to + r-t relation ultimate accuracy in r/t : ~10m needs ~ 2.5×104 good /chamber O (108) -triggers (geometry +  included) + temperature+B-field corrections + a lot of computing. Calibrazione del rivelatore di Muoni: ATLAS t(ns) • before pp data : • average r-t; accuracy: 100200 m • cosmics in ATLAS (105/day×100days  ok) r(mm) Atlas-CMS workshop, Bologna 24/11/06

  15. Allineamento del rivelatore di Muoni: CMS Misure dal CMS MagnetTest –Cosmic Challenge “(MTCC”): dai muoni cosmici (dati MTCC ) dal sistema di allineamento dei mu misure dalle tracce misure del “survey” L’ obiettivo di una precisione ~100 mm sembra essere raggiungibile… Atlas-CMS workshop, Bologna 24/11/06

  16. CMS: Muoni Cosmici in caverna Frequenza attesa in caverna (barile) [ ricostruzione muoni “StandAlone”, usata in MTCC ] - ~500 Hz nel Barile (significativamente minore negli endcaps) 1 track events … 3 2 “2 tracks” events ~5105 muoni /camera/giorno (soprattutto nei sect.3-5, 9-11) 1 12 Atlas-CMS workshop, Bologna 24/11/06

  17. “Pre-allineamento “ Dati cosmici, nella stessa “ruota” (~poche ore di DAQ in caverna) ~150mm - Controllo delle misure col LASER @ B=0; - LASER necessario con B acceso…. Atlas-CMS workshop, Bologna 24/11/06

  18. Allineamento con le tracce del sistema dei muoni in ATLAS : introduzione Two “alignment modes” were tested in H8 2004 setup: • Absolute alignment:Reconstruct the chamber positions using only the optical sensor responses, the knowledge of their positions and their calibrations. • Relative alignment: Assume chamber positions to be known at a given time (reference geometry) and use sensor responses to infer the chamber movements with a precision of < 20 µm since that time. Both modes are internal to the barrel or to the endcap muon spectrometer. There is no information that links the aligned muon system to the other detectors ID, calorimeters e.t.c.: use tracks! Target: achieve30 mmaccuracy on sagitta measurement

  19. Test allineamenti nel Barile: movimenti controllati delle camere • Complex movements (rotations+ displacements) of all barrel chambers • Relative mode: • Both barrel and endcap relative alignment is known within 20 µm • Absolute mode: • Endcap: Sagitta mean value ~150 µm • Barrel: Sagitta mean value ~350 µm

  20. Allineamento con le tracce del sistema dei Muoni in CMS • Meno importante che in ATLAS • esiste Link Tracker-Mu nel • sistema hardware • Utile “cross-check”: • (medio/lungo periodo) • e.g. usando Wmn : ~20 giorni di presa dati @ L=1033 [N.B: si assume perfetta conoscenza del campo magnetico…] Rivelatore ideale sd~100mm 2 su 4 camere disallineate in un settore di CMS tutte le camere sono disallineate Estimatore dello spostamento dalla posizione ideale di una singola camera del barile Atlas-CMS workshop, Bologna 24/11/06

  21. Disallineamnti: impatto sulla fisica Impatto su possibili scoperte ‘iniziali’: Esempio: Z’ 2m CMS, L= 100 pb-1 (Zh in SO(10) GUT model) potrebbero mostrarsi presto… “ideal” “first data” scenario ideal + Atlas-CMS workshop, Bologna 24/11/06

  22. Campo magnetico • Understanding magnetic field is important for mass scale • W mass requires overall field integral to < 0.05% (10 G in the 2T Field), other physics processes 0.1%. Principle of the mapping: • Scanning ID volume with 48 Hall probes mounted on two rotating arms in  in radial position from 11.8 to 105.8 cm: • Hall probes calibrated to about 1G with NMR readings • Four NMR probes are permanently placed at large radius at z=0; • Mapping campaign from June 29th to August 7th • Configuration: Complete barrel, no shielding disk, minivan on side C • 139000 measurements: 6 points/dm3; ATLAS Solenoid Atlas-CMS workshop, Bologna 24/11/06

  23. Campo magnetico: il solenoide di ATLAS • Field stability : the NMR shows a stability of about 0.003 T • The measurements have been fitted with a detailed model of the solenoidal field • Typical residuals: • Br : 6 G Bz: 7G Bf: 3 G • Use the measurement an the field model to estimate the coil position in space:the survey position is found within an accuracy of about 0.5 mm • Contributions of the iron predicted to be about 5% of the field is confirmed by the measurements • Goal within reach to meet the the requirement of a solenoidal field map with an absolute precision of 5·10-4 . • Work in progress for further improvments Atlas-CMS workshop, Bologna 24/11/06

  24. Misure del campo magnetico in ATLAS durante il test del Toroide: RisultatiPreliminari • Configuration: only Tile, no Endcap Toroids, no Solenoid • forces on the edge of the coil weaker ; coil shape different w.r.t the final layout Coverage complete (up to DB problems) Partial coverage: A only, C only or several chambers missing The ATLM model Atlas-CMS workshop, Bologna 24/11/06

  25. Most of the results here from 14000 A test 21000 Amp!(nominal is 20500) • Calculation done with ATLM (10kA, z = 0, R = 7.61 m) and scaled using the magnet current current (amp) NMR(T) calculation (T) DB/B(%) 12000 0.37035 0.36936 0.26 13000 0.40118 0.40014 0.26 • B gradient at NMR location is < 0.5 mT/cm • Work in progress to correct for the probes position. Atlas-CMS workshop, Bologna 24/11/06

  26. Campo magnetico: CMS Riproducibilita’ a livello di pochi Gauss; grande quantita’ di dati disponibili (misure ridondanti …); analisi in corso CMS magnet test: esempio di mappa a 3.8 T (Oct. ‘06) Br(T) Bz, r fissato B radial component different r different probes Atlas-CMS workshop, Bologna 24/11/06

  27. Calibrazione in impulso: Le risonanze determineranno la conoscenza della scala in impulso ( controllo mappa campo magnetico & allineamenti) ~30 MeV stat.error. CMS: 20 giorni di presa dati @L=1032 [≡200 pb-1] 2m in Barrel (|h|<0.8) 1m in “overlap” (0.8<|h|<1.2) 1m in endcap (|h|>1.2) Atlas-CMS workshop, Bologna 24/11/06

  28. Calorimetri E.M. ATLAS Pb-liquid argon sampling calorimeter with Accordion shape, covering || < 2.5 H   : to observe signal peak on top of huge  background need mass resolution of ~ 1%response uniformity (i.e. total constant term of energy resolution)  0.7% over || < 2.5 the same holds for CMS, of course… Atlas-CMS workshop, Bologna 24/11/06

  29. Calibrazione del Calorimetro • The constant term c=cL  cLR; • The local constant term, cL: • Geometry (residual Accordion modulation) • Mechanics (absorber & gap thickness) • Calibration (with pulse test: amplitude uniformity, etc …) • The “long-range” constant term cLR (from module-to-module miscalibration); • The absolute energy scale Use test beam measurements, cosmic ray run, pp collisions Atlas-CMS workshop, Bologna 24/11/06

  30. < > = 2.2 mm   9 m EM Calorimeter, ATLAS • Geometry: (e.g. deviation from Accordion modulation): ~ 0.3%; • Construction phase: thickness of all 1536 absorber plates (1.5m long, 0.5m wide) within ~ 10mm  response uniformity <~ 0.3%; • Pulse-Test and Testbeam: calibration accuracy of each module ~ 0.4%; • Overall “local” constant term: 0.5-0.6%. • Overall EM-scale: 1-2%. Main uncertainty from test beam extrapolation is probably temperature; • “Misalignment” effects: • Overall position of main elements: ~few mm • Sagging/Pear Shape: ~1-2mm effect vs phi (barrel) Da dove si parte? Test-beam data Uniformity: e- 245 GeV energy 0,44% Resolution: e- 245 GeV energy 0,7-0,9% Comb TB 2004: 0.55 % over ~30 cells Atlas-CMS workshop, Bologna 24/11/06

  31. Muon signal in barrel ECAL Test-beam data S() / (noise) 7  EM Cal., ATLAS Test-beam data • Cosmic muons: • find dead/noisy channels; cabling errors; compare with test beam data; • Check uniformity at the level of 1% accuracy; with <3 months of cosmics runs we can correct the calorimeter response variations vs h to 0.5% ; • Checks on drift time accuracy, at the level of 1ns accuracy, see plot Timing Atlas-CMS workshop, Bologna 24/11/06

  32. Calibrazione con i primi dati • 900 GeV data: • Huge uncertainty on luminosity. But Z,W are excluded as calibration probes. • Min.Bias • Jets • J/psi O(103) events with Et~5GeV for 1 day @ 1029cm-2s-1 • Inclusive electrons • 14 TeV data: • 10 pb-1 : (105s at 1032cm-2s-1): 5.103 Z, 105 W events, “inclusive” electrons (also Upsilon) • Overall scale in EM barrel, and EMEC OW. • EMEC IW need e-id without tracker. Probably OK for Z identification. ~250 events Barrel-IW per side • Inter-region calibration with Z ~ 1-1.5% • 100 pb-1: 5.104 Z, 106 W • Stat. Error on energy scale <0.1% • Inter-region calibration with Z ~0.5% • Non-linearity checks Atlas-CMS workshop, Bologna 24/11/06

  33. ECAL calib: CMS [vedi Zotto, commissioning talk] Punto di partenza: misure in laboratorio(~4%) + test su fascio (5 SuperModuli) + cosmici… Tbeam vs Cosmic data Calib.coeff. Cosmic data simulation Atlas-CMS workshop, Bologna 24/11/06

  34. ECAL : CMS All’ inizio con i dati pp: intercalibrazione basata sulla “f-symmetry” Barrel Endcap ~107 L1 jet triggers (10 h data taking @ 1KHz L1 rate) Limite sistematico (Tracker material budget…) precisione raggiungibile: ~ 1.5 - 2.0 % Atlas-CMS workshop, Bologna 24/11/06

  35. calibrazione di ECAL in CMS Serve il Tracker allineato & ben capito… Successivamente : E/p (da W en ) Endcap, 7 fb-1 Confronta con lumi richiesta da H gg : Barrel precisione raggiungibile (giusto in tempo…) NOT for 2008… Int.luminosity Atlas-CMS workshop, Bologna 24/11/06

  36. Calibrazione di ECAL in CMS + calibrazione “in situ” con Zee (independente dal Tracker): Precisione dell’ intercalibrazione degli anelli a h constante: 370 events/ring : ~ 2fb-1 Atlas-CMS workshop, Bologna 24/11/06

  37. Calorimetri Adronici • Cell calibration: • Reference scale (starting point) for individual cell calibration = EM scale • LAr: testbeam and calibration systems: about 1% accuracy on EM scale • Tilecal: testbeam data, Cs calibration ~ 3 % precision on EM scale • Cosmic muons, beam-halo muons • Useful in many aspects • Largon: finding dead channels, cabling errors… • Compare to muon test beam data • Trigger with Tilecal under study • Beam-gas hadrons • Channel mapping; • Study their properties and how to reject them… Atlas-CMS workshop, Bologna 24/11/06

  38. Minimum Bias & jet events • Monitoring detector response stability: with ~ 1-8x106 triggers to reach 1% stability • Cell-to-cell calibration • Using phi-symmetry of MB triggers, inter-calibrate cells with equal dimensions/positions (2x64 cells) • Jet calibration; based on weights estimated from Monte Carlo studies; ingredients: • Jet fragmentation modelling: electromagnetic jet energy fraction, energy and multiplicity of charged hadrons, etc.. • Hadronic shower models, benchmarked in comparison with test beam data; • Description of dead material insimulation (fraction of “lost energy” in dead material from ~few% to 15 %); studies with material distortion will take place in next months. • Validation of jet adrons: look to isolated hadrons and use E/pto understand first agreement between data/MC at EM scale than use hadronic scale and check hadron calibration. • Example :  + jets Gamma+jet has high QCD background up to about 150 GeV but reaches higher pT. First estimate indicates that a statistical error ~1% in the central region up to pT 400 GeV with 100pb-1. Realistic trigger studies have to be carried out; see next slide Atlas-CMS workshop, Bologna 24/11/06

  39. Parton level Particle level Cone 0.7 Reconstruction level Cone 0.7 pT balance 5% (pTγ+pTparton)/2 (GeV) Calibrazione usando i dati: Gamma + jet • Validation: comparing balance at reconstruction, MC jet and parton level gives indication on source of unbalances and deviation between MC and data: • Source of pT unbalance: • calibration biases • contribution of UE event • losses due to unclustered energy. • effect of ISR contribution. • pT balance at parton level is within <1% ISR effect is small • Cone 0.7 is correctly calibrated (red vs blue) and losses due to out of cone energy are compensated by UE (blue vs black). pT gamma UE pT jet (pTγ+pTparton)/2 (GeV) Atlas-CMS workshop, Bologna 24/11/06

  40. Jets: conoscenza a “startup” (MC…) CMS study: MC jet corrections: Starting point … (+test beam meas.+rad.source calib….) Next: Calib.from pp data Atlas-CMS workshop, Bologna 24/11/06

  41. Calibrazione dei jets dai dati CMS QCD dijets balancing: relative calibration “barrel leading jet”(|h|<1) against ‘probe’ jet (any |h|) pT>120 GeV, prescaled to 2.5 Hz ~1 hour data taking Inclusive one jet QCD cross section at low pT is a benchmark measurement: 1% error on jet scale leads to 5% error on cross section at 300 GeV ATLAS StartUp: 100 pb-1 1 x 1031 Prescales Total rate 22 Hz Atlas-CMS workshop, Bologna 24/11/06

  42. Energia trasversa mancante: • Fake Etmiss rejection • Fake/badly measured muons • Shower leakage both from punchtrough and cracks • energy lost in dead material, cracks • Etmiss in direction of jet , jet in region with poor responce,… First require detailed understanding of instrumental Etmiss sources event cleaning: Beam halo muons, beam gas collisions, cavern background, displaced vertices (use calo cells timing, event velocity…) dead/noisy/hot cells in calorimeters EtMiss in early data:resolution with minimum bias and W-jets Minimum bias: Possible to test EtMiss resolution up to ET=300GeV W+jets: evaluate EtMiss resolution up ET=1 TeV (L=100 pb-1) Atlas-CMS workshop, Bologna 24/11/06

  43. EtMiss in early data: in situ scale determination with Z   Z  lepton-hadron Expect 70000 in 100pb-1 7000 with pt(lep)_true>15GeV Rec  mass Signal Z   Inclusive W e Inclusive W  top Single Trigger lepton (PT=15 GeV) Apply kinematic, Tau-Id and reconstructed mass cuts Expected in 100pb-1 ~ 300 evts with ~ 20% backgd Possible to loosen cuts to increase statistics? Or more severe cuts necessary to reduce bb backgd? <> ~ 90  ~ 16 Rec  mass vs EtMiss scale +3% Results still preliminar due to low background statistics Need to have also a bb sample Trigger-aware analysis and Cuts tuning -3% - 10 % +10 % Atlas-CMS workshop, Bologna 24/11/06

  44. Triggers • Initial luminosity: aboutL=1031cm-2s-1; • Bunch spacing: 75 ns; • We know which “25 ns” bunch is filled-in; • Excellent opportunity to relax the timing of the several systems • No real problem to identify the Bunch Crossing • Background in the muon system: is expected to be not a concern even in the more pessimistic scenarios • Trigger: time calibration not criticalrelax the pulse width of the trigger detector signals • Low occupancy of the muon chambers • Data Acqusition rate: 200 events/s, for 1.5 MB average event size; it can go up to 400 MB/s. Trigger commissioning / syncronization (‘local’, relative, absolute…): expected to be done in the first days of data taking (**some** info also from cosmic exercise, but different time pattern w.r.t particles fro pp interaction) Atlas-CMS workshop, Bologna 24/11/06

  45. Sync.example: CMS muon DT chambers Syncronizing the muon passage on a chamber with the internal clock of the chamber trigger device: Optimal phase: peak -12.5 ns Scan on internal clock phase in each DT chamber (can be parallelized…) 10 ns 9 ns 11 ns… Needs 0(105 ) “prompt” muons Mean time (ns) Atlas-CMS workshop, Bologna 24/11/06

  46. Commissioning @ startup: muoni Ldt = 100 nb-1 2007 LHC pilot run # ev / 10 nb-1 ~ 15000 prompt m from b/c, pT>6 GeV |h|<2.4 Sqrt(s)=900 GeV Atlas-CMS workshop, Bologna 24/11/06

  47. Ldt ~ 10 nb-1 ~ 50000 prompt m from b/c, pT>6 GeV W Sqrt(s)= 14 TeV Muoni “Prompt” : 900 GeV vs 14 TeV Normalization to sinel= 50 mb Pythia 6.2 ,‘default’ min.bias settings Ldt ~ 100 nb-1 ~ 15000 prompt m from b/c, pT>6 GeV, |h| < 2.4 ~ 100 W Sqrt(s)=900 GeV [ in addition, there will be substantial number of K/pm ] Atlas-CMS workshop, Bologna 24/11/06

  48. Trigger menu • Object (GeV) rate(Hz) prescaling • Muon 6(5) 40 6 • Muon 20 14 1 • Dimuons 2x6 (2x5) 3 1 • e/g/t 25 20 10 • e/g/t 15 20 70 • 2e/2g/2t 2x15 20 1 • Jets: 25,50,90,200 22 104,103,25,1 • Dijets,Trijets,... 10 ? • ETMiss 25,100 30 ? • Minimum Bias 20 5x104 • and/or random trigger • Monitoring/Diagnostics 20 1 • TOTAL RATE ~220 ATLAS example, for L= 1031 : • Trigger Commissioning • The understanding of the LVL1 trigger is one of the most crucial points for the trigger at the startup • we can run only with the LVL1 “active”, HLT “transparent” • In a second phase insert the HLT • in the Trigger system CMS, single jets, L= 1032 pre-scaling example: ~8 Hz Atlas-CMS workshop, Bologna 24/11/06

  49. Segnali di fisica a “Startup”? Non molto di piu’ che jets da QCD (includendo b-jets…e leptoni ‘prompt’ che li accompagnano…) Atlas-CMS workshop, Bologna 24/11/06

  50. Misure con gli eventi di Minimum Bias • Acceptance limited in rapidity and pt • Rapidity coverage • Tracking covers |h|<2.5 • pT problem • Need to extrapolate by ~x2 • Need to understand low pt charge track reconstruction • Triggering • MBTS • Random trigger+track trigger Soft physics, pile-up at higher luminosities, calibration of experiment v12.0.2 Atlas-CMS workshop, Bologna 24/11/06

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